A 3D-printed blood-brain barrier model with tunable topology and cell-matrix interactions

Recent advances in 3D bioprinted neural models: A systematic review on the applications to drug discovery

The design of neural tissue models with architectural and biochemical relevance to native tissues opens the way for the fundamental study and development of therapies for many disorders with limited treatment options. Here, we systematically review the most recent literature on 3D bioprinted neural models, including their potential for use in drug screening. Neural tissues that model the central nervous system (CNS) from the relevant literature are reviewed with comprehensive summaries of each study, and discussion of the model types, bioinks and additives, cell types used, bioprinted construct shapes and culture time, and the characterization methods used. In this review, we accentuate the lack of standardization among characterization methods to analyze the functionality (including chemical, metabolic and other pathways) and mechanical relevance of the 3D bioprinted constructs, and discuss this as a critical area for future exploration. These gaps must be addressed for this technology to be applied for effective drug screening applications, despite its enormous potential for rapid and efficient drug screening. The future of biomimetic, 3D printed neural tissues is promising and evaluation of the in vivo relevance on multiple levels should be sought to adequately compare model performance and develop viable treatment options for neurodegenerative diseases, or other conditions that affect the CNS.

Light-based 3D bioprinting techniques for illuminating the advances of vascular tissue engineering

Vascular tissue engineering faces significant challenges in creating in vitro vascular disease models, implantable vascular grafts, and vascularized tissue/organ constructs due to limitations in manufacturing precision, structural complexity, replicating the composited architecture, and mimicking the mechanical properties of natural vessels. Light-based 3D bioprinting, leveraging the unique advantages of light including high resolution, rapid curing, multi-material adaptability, and tunable photochemistry, offers transformative solutions to these obstacles. With the emergence of diverse light-based 3D bioprinting techniques and innovative strategies, the advances in vascular tissue engineering have been significantly accelerated. This review provides an overview of the human vascular system and its physiological functions, followed by an in-depth discussion of advancements in light-based 3D bioprinting, including light-dominated and light-assisted techniques. We explore the application of these technologies in vascular tissue engineering for creating in vitro vascular disease models recapitulating key pathological features, implantable blood vessel grafts, and tissue analogs with the integration of capillary-like vasculatures. Finally, we provide readers with insights into the future perspectives of light-based 3D bioprinting to revolutionize vascular tissue engineering.

Effects of Drag-Reducing Polymers on Hemodynamics and Whole Blood-Endothelial Interactions in 3D-Printed Vascular Topologies

Most in vitro models use culture medium to apply fluid shear stress to endothelial cells, which does not capture the interaction between blood and endothelial cells. Here, we describe a new system to characterize whole blood flow through a 3D-printed, endothelialized vascular topology that induces flow separation at a bifurcation. Drag-reducing polymers, which have been previously studied as a potential therapy to reduce the pressure drop across the vascular bed, are evaluated for their effect on mitigating the disturbed flow. Polymer concentrations of 1000 ppm prevented recirculation and disturbed flow at the wall. Proteomic analysis of plasma collected from whole blood recirculated through the vascularized channel with and without drag-reducing polymers provides insight into the effects of flow regimes on levels of proteins indicative of the endothelial-blood interaction. The results indicate that blood flow alters proteins associated with coagulation, inflammation, and other processes. Overall, these proof-of-concept experiments demonstrate the importance of using whole blood flow to study the endothelial response to perfusion.